Key pulley segment features, segment stack configuration, and cam and roller design and actuation in a synchronized segmentally interchanging pulley transmission system

ABSTRACT

A key pulley segment in a synchronized, segmentally interchanging pulley transmission system is either first or last in a pulley segment set to engage an endless member. The first or last key segment teeth to engage or disengage, respectively, are shortened or completely trimmed, and the adjacent pulley segment to the key segment is elongated such that the inward portion of the tooth profile extends toward the key segment. Shortened tooth or teeth and an elongated adjacent segment together allow for many pulley segments to be designed as key segments. Completely trimmed teeth may be engineered to create a supporting surface for the endless member on the key segment. The elongated adjacent segment may have an extending portion which slidably mates with the supporting surface of the key segment, thereby receiving radial support therefrom. Multiple pulley segments from different pulley segment sets may be connected or constructed to move together in a unified stack, and may be staggered such that any one segment may be in an engaging position with the endless member when the unified stack is moved along the axis of rotation. Unified stacks may have guiding rails on both inner and outer radial surfaces, and the pulley assembly may have mating features that receive such guiding rails. Any number of the pulley segments in a unified stack may be key pulley segments. Pulley segments of a stack may be vertically separated into one or more unified stacks. Unified stacks may be moved by way of a cam or roller cam system, where each unified stack has a slidably or ratably attached roller and roller-arm. Chassis-mounted cams engage the rollers outside of the contact zone, rollers and roller-arms are moved into and out of engagement with the cams, and individual segments of a unified stack are moved into or out of engagement. Rollers may be actuated into and out of engagement by electromagnets, fixably mounted in an array. Rollers may discretely engage with multiple cams, by way of several electromagnet-arrays, and thereby complete several stack axial motions. Electromagnets in an array may be selectively energized to move selected rollers to an active position in order to effect key pulley segment engagement, stack axial movement and transition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/479,032 filed on Apr. 26, 2011 and entitledSYNCHRONIZED SEGMENTALLY INTERCHANGING PULLEY TRANSMISSION SYSTEM, theentire content of which is incorporated herein by reference. Thisapplication is related to International PCT Application Publication No.WO 2005/111463 filed on May 19, 2005 and entitled SYNCHRONIZEDSEGMENTALLY INTERCHANGING PULLEY TRANSMISSION SYSTEM.

FIELD OF THE INVENTION

The present invention relates to transmission systems, and moreparticularly to mechatronic variable speed drives.

BACKGROUND OF THE INVENTION

A synchronized, segmentally interchanging pulley transmission system(“SSIPTS”) is the subject of International PCT Application PublicationNo. WO 2005/111463, with a priority date of May 19, 2005, the entirecontent of which is incorporated herein by reference.

The development of the SSIPTS has revealed several novel additionalfeatures which may enhance the operation of such a mechatronic variablespeed drive system.

Accordingly, there is a need for novel improvements and additionalfeatures for use in the SSIPTS.

SUMMARY OF THE INVENTION

In one aspect, there is provided a key pulley segment, acting as onepulley segment in a pulley segment set, in a synchronized segmentallyinterchanging pulley transmission system, and having a distalrelationship with the teeth of a second pulley such that simultaneousengagement of an endless member is possible, incorporating one or moreshortened or completely trimmed key pulley segment teeth, which teethare either first or last in the pulley segment set to engage the endlessmember.

In accordance with another aspect, there is provided a key pulleysegment, acting as one pulley segment in a pulley segment set, in asynchronized segmentally interchanging pulley transmission system, andhaving a distal relationship with the teeth of a second pulley such thatsimultaneous engagement of an endless member is possible, incorporatingan adjacent pulley segment with elongated or overhanging teeth features,with an extending segment portion which may or may not slidably matewith a supporting surface of the key pulley segment.

In accordance with another aspect, there is provided a supportingsurface on a key pulley segment for an endless member, created by theshortening or complete trimming of one or more key pulley segment teeth,in a synchronized segmentally interchanging pulley transmission system.

In accordance with another aspect, there is provided a unified stackcomprised of multiple, staggered pulley segments, vertically connectedor constructed onto one or more slidably movable components, with matingfeatures and guiding rails on their inner and outer surfaces, any ofwhich pulley segments in the unified stack may engage an endless member,in a synchronized segmentally interchanging pulley transmission system.

In accordance with another aspect, there is provided a core pulley in asynchronized segmentally interchanging pulley transmission system, withguiding rails which mate with the mating features on a inner surface ofa most proximate unified stack comprised of multiple, staggered pulleysegments, vertically connected or constructed onto one or more slidablymovable components, where the guiding rails of said core pulley may alsofunction as teeth capable of engaging the endless member.

In accordance with another aspect, there is provided a series of one ormore cams, in a synchronized segmentally interchanging pulleytransmission system, affixed or fixably mounted to a chassis or housing,and a series of rollers, fixed members or other such cam followers, witha roller arm affixed to each roller, where the roller and roller arm areslidably or notably mounted to unified pulley segment stacks, togethercapable of moving a unified pulley segment stack by the movement of eachroller into and out of an active position, enabling its engagement witha cam, in a manner such that individual pulley segments of said stackmay be moved into or out of an engaging position.

In accordance with another aspect, there is provided the actuation of aroller, or fixed member or other such cam follower, and its roller-arm,together into its active position, before the point of engagement of theroller with a cam, and out of its active position, after its point ofengagement with the cam, by an array of fixably mounted electromagnetslocated near the path of a roller, in proximity to or as part of the camin a synchronized segmentally interchanging pulley transmission system.

In accordance with another aspect, there is provided an arrangement ofmultiple cams, in a synchronized segmentally interchanging pulleytransmission system, such that discrete sequential engagement by aseries of rollers, or fixed members or other such cam followers,together with the corresponding series of attached unified pulleysegment stacks, is available, such that a unified pulley segment stackmay move into a plurality of positions, which positions correspond tothe several engaging positions of pulley segments contained in thestack.

In accordance with another aspect, there is provided an array of fixablymounted electromagnets, arranged such that a feature on a pulley segmentor pulley segment stack in a synchronized segmentally interchangingpulley transmission system may be discretely actuated, by thesynchronization of the energizing of one or more selectableelectromagnets to the position and motion of the desired pulley segmentfeature, which feature may be the pulley segment or pulley segment stackitself, a roller, a cam follower or other fixed member, or some otheractuator feature, when the desired feature passes proximate to theselected electromagnet or electromagnets in the array.

In accordance with another aspect, there is provided a system ofsequencing the energization of fixably mounted electromagnets in anarray, such that pulley segment features, which features may be a pulleysegment or pulley segment stack itself, a roller, a cam follower orother fixed member, or some other actuator feature, such that anindividual pulley segment or pulley segment stack may be discretelyactuated, in a synchronized segmentally interchanging pulleytransmission system.

These and other features, advantages and objects will be furtherunderstood and appreciated by those skilled in the art by reference tothe following specification, claims and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described by way of example only with referenceto the accompanying drawings.

FIG. 1 shows a side sectional view of a SSIPTS core pulley and pulleysegment sets, including a key pulley segment and adjacent pulleysegment.

FIG. 2 a shows a side view of a core pulley, a pulley segment setincluding key pulley segment and adjacent pulley segment, and a toothedendless member, where said endless member is simultaneously engaging theteeth of the core pulley and the teeth of the key pulley segment suchthat some of the teeth of the endless member are demonstrated to be onthe supporting surface of the trimmed area of the key pulley segment,such that the bending radius of the endless member is increased.

FIG. 2 b shows a close view of the same core pulley, some pulleysegments of the same pulley segment set (including the same key pulleysegment and adjacent pulley segment), and the same endless member as inFIG. 2 a, and showing the same transition and action.

FIG. 2 c shows a dose view of part of the core pulley, a key pulleysegment, an adjacent pulley segment, and a pulley segment without theendless member, allowing a view of the trimmed teeth and supportingsurface of the key pulley segment, and the overhanging, extended area ofthe adjacent pulley segment.

FIG. 3 a shows a perspective side-front view of a unified pulley segmentstack.

FIG. 3 b shows a perspective side-rear view of a unified pulley segmentstack.

FIG. 4 shows a perspective side-front view of the pulley assembly, withthe pulley segments staggered in unified pulley segment stacks, some ofwhich unified pulley segment stacks are in transition between positionsduring a SSIPTS shift.

FIG. 5 shows a top view of the endless member engaging two SSIPTSsystems as some of the unified pulley segment stacks in the lower SSIPTSare seen in transition between positions.

FIG. 6 shows three views of the pulley assembly, with unified pulleysegment stacks currently aligned such that the endless member may engageone pulley segment set.

FIG. 7 shows guiding rails and mating features, as seen on the corepulley.

FIG. 8 shows a side view of cams where the cam channels are obscured,and rollers, trigger arms, trigger arm pivots, and electromagnetmounting on unified pulley segment stacks.

FIG. 9 shows a perspective view of unified pulley segments stacksarranged as they would be with a pulley assembly, with rollers,roller-arms, and cams.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention operates as parts of, or in conjunction with, aSSIPTS, a mechatronic variable speed drive that changes ratio underload, and involves a plurality of pulleys, divided into segments, whichsegments move in channels or on rails along the rotational axis, intoand out of the path of a toothed belt or chain (an “endless member”).This paragraph, and several of those following, briefly describe thefunctioning of a SSIPTS, in the context of which the present inventionoperates.

In a SSIPTS, as segments of a plurality of toothed, concentric andcoaxial pulleys move axially, along channels or rails, into and out ofthe path of an endless member, from either side thereof, pulley segmentmovement is coordinated by a synchronization and timing system, and thecoordinated movement of pulley segments allows the endless member tochange engagement between a plurality of concentric pulleys, withoutdisrupting their rotation or the delivery of power. This is accomplishedby enabling the teeth of the endless member to be continuously engagedby at least one toothed pulley, and at some points—when the endlessmember is changing engagement between pulleys—engaged by both theengaging and disengaging pulleys, in transition.

The continuous engagement is made possible by the designation of certainpulley segments as “key pulley segments”, the initial pulley segmentsinvolved in the transition from a smaller pulley segment set and thelast pulley segments involved in the transition to a smaller pulleysegment set. Key pulley segments are defined by their angularrelationship with one or more smaller pulley segment sets, such that thecircumferential position of the key pulley segment allows it to engagethe endless member while the endless member is still engaging thesmaller pulley segment set, without introducing significant interferenceor slack.

In the SSIPTS, each pulley segment is individually moved by the systemactuator, in an axial direction from its non-engaging position to itsengaging position and from its engaging position to its non-engagingposition, as controlled by the system sequencer, which ensures that theappropriate pulley segments move from their engaging position to theirnon-engaging position, or from their non-engaging position to theirengaging position, in the order and timing that is optimal to keep theendless member engaged with pulley segments of more than one set duringits transition from a disengaging pulley segment set (an “origin set”)to an engaging pulley segment set (a “destination set”).

Once a key pulley segment moves into its engaging position, eachfollowing pulley segment in the same pulley segment set is subsequentlymoved into its engaging position as it passes outside of the “contactzone” (the angular area of contact between the endless member and theorigin set). Thus, the following pulley segments continue the engagementof the endless member with the destination set. The actuator moves eachindividual pulley segment at a speed sufficient for it to complete itsmovement between its engaging position and its non-engaging position, ineither direction, during the period of time while they are outside thecontact zone.

Enhanced Features of the Key Pulley Segment

One method of engineering a pulley segment to be a key pulley segment isto rotate the entire pulley segment set (ring of pulley segments whichtogether act as a pulley) around the axis of rotation, until they arecircumferentially aligned in relation to a second pulley (or pulleysegment set) such that the key pulley segment will have a distalrelationship with the teeth of said second pulley such that the endlessmember may be engaged with the teeth of the key pulley segment and theteeth of second pulley simultaneously. Said distal relationship largelyconcerns the pitch of the teeth of the endless member, and the positionof the teeth of said second pulley which are approximately tangential tothe teeth of said key pulley segment.

Another method of engineering a pulley segment to be a key pulleysegment is to shorten the tooth that is either first in the pulleysegment set to engage the endless member, or the last in the pulleysegment set to engage the endless member. This will allow a pulleysegment in a pulley segment set to be a key pulley segment withoutrotating the entire pulley segment set in relation to another pulley orpulley segment set, which will enable multiple pulley segments in onepulley segment set to be key pulley segments.

Referring to FIG. 1, the shortened tooth 104 on a key pulley segment 103may be seen. One potential issue when designing a shortened tooth 104 ona key pulley segment 103 is that it may affect the roundness of thepulley segment set when acting as a pulley. To mitigate the change inshape, the adjacent pulley segment 105 to a key pulley segment 103 maybe elongated in such a way that the inward portion of the tooth profile(the “valley” located between the segment teeth) will extend toward keypulley segment 103. Elongated as such, the adjacent pulley segment 105extends toward said key pulley segment 103, creating a valley 106between the shortened tooth 104 of the key pulley segment 103 and theadjacent pulley segment 105 which will support the tooth of the endlessmember that protrudes toward the space between said key pulley segmentand said adjacent pulley segment, when both said key pulley segment andsaid adjacent pulley segment are in the position in which they mayengage the endless member. This extension of said adjacent pulleysegment will ensure that the pulley segment set will be round, such thatthe endless member will cooperate with all pulley segments smoothly,preventing vibration and inefficiency.

The combination of these two design features, both the shortened tooth104 on the key pulley segment 103, and the elongation of the adjacentpulley segment 105 to create a valley 106 with the shortened tooth 104of the key pulley segment 103, allows for many pulley segments 48 to bedesigned as key pulley segments, such that the endless member may betransitioned from either a larger pulley segment set to a smaller pulleyor pulley segment set, or from a smaller pulley or pulley segment set toa larger pulley segment set, without unwanted interference between anyoperating features, and without undesired slack in the endless member.The transmission of power from pulley segment sets via the endlessmember to a cooperating pulley or a cooperating second pulley segmentset (a second instance of the SSIPTS) may occur at high speed becausethe roundness of the pulley segment sets, as the endless member engagesthem, may be maintained.

In addition, completely trimmed teeth may be engineered to create asupporting surface for the endless member on the key pulley segment.Referring now to FIGS. 2 a through 2 c, the elongated adjacent pulleysegment 105 is shown, and pulley segment teeth 104 are trimmed away, andin their place there is created a supporting surface 159 which preventsthe endless member 47 from bending sharply. The supporting surface 159is curved, having an arbitrary radius that is defined by someone skilledin the art.

The radius of the supporting surface may be altered to change thetension of the endless member teeth on the pulley segment teeth, or toremove unwanted interference or slack, without changing thecircumferential relationship between the two pulley segment sets intransition (comprising the origin set and the destination set).

Another unique feature of the functioning of the key pulley segment isthe elongated or overhanging teeth feature of the adjacent pulleysegment. The pulley segment which is adjacent to the sprocket may havean extending portion which slidably mates with the supporting surface ofthe key pulley segment, thereby receiving radial support from the keypulley segment. The overhanging teeth of the adjacent pulley segmentreplace the “missing” teeth that have been shortened or completelytrimmed on the key pulley segment as previously described, and in sodoing complete the pulley segment set such that there are no missingteeth while all the segments of the pulley segment set are in theengaging position.

The geometric relationship of the overhanging segment teeth andsupporting surface may optimize the functioning of the key pulleysegment. The key pulley segment supporting surface and the overhangingteeth may have round, or partially cylindrical, surfaces where theendless member may be engaged. In order that the key pulley segmentsupporting surface and the overhanging teeth supporting surface do notbecome stuck or bound in the event of twisting or misalignment of theendless member, one or both supporting surfaces may have features whichisolate the point of contact such that the surfaces will not bindtogether. Such features may be designed by someone skilled in the art,and may comprise an engineered bump, nub, or a rail, or multiples orcombinations thereof, amongst other features.

Alternative Pulley Segment Stack Configuration and Implementation

A plurality of pulley segments in a pulley segment stack may be designedto move together. In this case, pulley segments from different pulleysegment sets that are proximate to each other may be fused, bonded,connected or constructed into a stack that may be actuated as one object(a “unified stack”). FIGS. 3 to 7 show differing views of theconfiguration and operation of said unified stack.

Pulley segments in a unified stack may be staggered such that any one ofsaid pulley segments may be in its engaging position when the unifiedstack is moved along the axis of rotation of the pulley assembly. FIGS.3 a and 3 b provide two isometric views of a staggered pulley segmentstack. Pulley segments 48 from different pulley segment sets that arevertically proximate are connected or constructed together into aunified stack 150. The pulley segment teeth 52 remain available toengage the teeth of the endless member when the unified stack 150 movesthe desired pulley segment 48 into the engaging position. When a pulleysegment is moved into its engaging position, the whole stack is moved,thus the pulley segment in the stack that was previously in the engagingposition must be simultaneously moved out of the engaging position. Inthis embodiment, moving one unified stack such that one of its segmentsengages must necessarily mean moving another stack such that itspreviously engaging segment disengages.

A unified stack may feature a set of guiding rails on its “downward” orradially “inner” surface, on the surface closest to the axis of rotationof the pulley assembly, on the “downward” or radially “inner” side ofthe pulley segment of the smallest pulley segment set, facing the axisof rotation. A unified stack may also feature a set of guiding rails onits “upward” or radially “outer” surface, on the surface furthest fromthe axis of rotation, on the “upward” or radially “outer” side of thepulley segment of the largest pulley segment set, facing away from theaxis of rotation.

The pulley assembly may have mating features that receive said innerguiding rails and may have another set of mating features that receivesaid outer guiding rails, holding the unified stack in relation to thepulley assembly, while permitting movement of the unified stack, on itssets of rails, parallel to the axis of rotation of the pulley assembly,thus allowing pulley segments in the unified stack to move into and outof their respective engaging positions. Said guiding rails and saidmating features on the unified stacks of the pulley assembly may obviatethe need for channels or rails on the lateral or side facets of thepulley segments, and the outer guiding rails on the outmost facing ofthe pulley assembly may obviate the need for, and function of, the corepulley, as in this embodiment the smallest pulley segment set becomesthe “first gear”. FIGS. 3 a and 3 b show outer mating features 151 andinner mating features 152. This embodiment may allow pulley segments tobe robustly housed—congregated on one single side of the endless memberin a single carousel, as opposed to the dual-carousel alignment in otherembodiments.

FIG. 4 shows an isometric view of the pulley assembly, as staggeredunified pulley segment stacks are shifting. Pulley segments 48 arearranged into multiple staggered unified stacks 150, with outer matingfeatures 151 and inner mating features 152, together with guiding rails153 mounted on the core pulley 154, which is itself mounted on the axle32 in the pulley assembly.

FIG. 5 shows a side view of the pulley assembly, as staggered unifiedpulley segment stacks are shifting. FIG. 5 portrays the driving pulleyassembly 155 b, and the driven pulley assembly 155 a, each mounted on anaxle 32. Unified staggered pulley segment stacks 150 may be furtherspecified as individual unified stacks 150 a through 150 j (unifiedstacks 150 d through 150 g are obscured from view and not shown). Thesecond-smallest pulley segment 48 in the unified stacks 150 c, 150 d,150 e, 150 f, 150 g, 150 h, 150 i and 150 j are in the engaging positionof the endless member 47, while the third-smallest pulley segment inunified stack 150 a has just moved into the engaging position, and the3^(rd) smallest pulley segment of unified stack 150 b has been actuatedand is moving into the engaging position. In this example, thethird-smallest pulley segment of unified stack 150 a is a key pulleysegment, and thus engages the endless member 47 first of its set.

FIG. 6 shows three views of the pulley assembly, with staggered pulleysegment stacks currently engaging in “second gear”.

Key pulley segments may or may not all be in one unified stack, and anynumber of the pulley segments in a unified stack may be key pulleysegments. A unified stack may contain no key pulley segments.

The core pulley may have teeth which may engage the teeth of the endlessmember, such that the teeth on the core pulley may also act as the railsof the core hub, which mate with the inner guiding rails of theproximate unified stack. FIG. 7 shows guiding rails 153 and matingfeatures 153, as seen on the core pulley 154.

The SSIPTS system actuator, alone or in conjunction with the SSIPTSsystem sequencer, may utilize an indexing system, ratcheting system orother system to move a unified stack, axially, into and out of positionsrelative to the path of the endless member, in order that each pulleysegment in said unified stack may move to its engaging position.

The pulley segments of a stack containing a pulley segment from eachpulley segment set may be vertically separated into one or more unifiedstacks. For example, if eight individual pulley segments verticallygrouped into one unified stack presents difficulty for the rail systemor other systems, separation into two sub-stacks each comprising fourvertically proximate segments may be desirable. In this example, in aSSIPTS employing eight pulley segment sets, the pulley segmentsemanating from the four smallest pulley segment sets may be constructedtogether into one unified stack, operated by one actuator mechanism,while the pulley segments emanating from the four largest pulley segmentsets may be constructed together in a second unified stack, operated bya second actuator mechanism.

The main benefit of the embodiment utilizing a unified stack is thereduction in the number of actuators, although characteristics ofstrength, weight, size and operability may be evaluated by someoneskilled in the art.

Design with Roller and Cam

Unified pulley segment stacks, composed of individual pulley segments,may be moved such that any pulley segment contained therein may be movedinto or out of an engaging position, by way of a cam or roller camsystem (the “stack axial motion”). In this configuration, each unifiedpulley segment stack has a roller which is slidably or ratably attachedto said stack, by way of a roller-arm or other supporting member. Saidroller may also be a fixed member or other such cam follower which islubricated or made of a material which is selected by someone skilled inthe art for its strength, wear and friction characteristics, but isreferred to hereafter as a “roller”.

One or more cams are incorporated into the functioning of the SSIPTS,which cams are affixed or fixably mounted to the chassis or housing, andare located in the zone where the pulley segments may not be engaged bythe endless member (the area outside the SSIPTS “contact zone”, whichmay be called the “non-contact zone”). In the non-contact zone, a cammay engage the roller and, through engagement, move a unified pulleysegment stack in a manner such that individual pulley segments of saidstack may be moved into or out of an engaging position.

Cams may be mounted in an axial or linear array, or may feature one ormore cams that are positionally interchangeable. One or more cams may bemounted in a movable manner, allowing it to accommodate several stackaxial motions.

The roller may be moved, in relation to the stack, into and out of aposition in which it may engage one of the cams (the “roller activeposition”). The roller may be mounted on a roller-arm or other movablesupporting member, which guides the roller between the roller activeposition and its inactive position. Said supporting member shall behereinafter referred to as the “roller-arm”. The mass of the roller androller-arm may be balanced with regard to the rotating or sliding axissuch that centripetal forces will act upon the position of the rollerpositively, negatively, or neutrally, as deemed preferential by someoneskilled in the art.

Referring now to FIG. 8, a series of unified pulley segment stacks 150is seen with the cam 156, and with a series of rollers 157 and rollerarms 158, where roller arms 158 a, 158 b, 158 c, 158 d, and 158 e are inthe roller active position, and roller arms 158 f, 158 g and 158 h arein the roller inactive position.

While the pulley segments of a stack are in the SSIPTS “contact zone”,the roller may be moved to the roller active position, such that thestack axial motion is commenced. The stack will then rotate into the“non-contact zone”, the roller will engage the cam, and the cam willconsequently move the roller and stack axially, such that one of thepulley segments of said stack will move from its engaging position toone of its non-engaging positions and, by the same motion, a secondpulley segment in said stack will move from one of its non-engagingpositions to its engaging position.

Cam Face Design

The surface of the cam which engages with the roller in the rolleractive position (the “cam engaging position”) may be a curve which isoptimized by someone skilled in the art to minimize the overall forcesand stresses involved in the stack axial motion, and to improvestability and reliability of the motion and positioning of the unifiedpulley segment stacks. Each cam may have a specific curve, which isoptimized for the overall pulley speed and other physical and operatingcharacteristics which are particular to the pulley segments which aremoved in the stack axial motion.

The cam may have a channel in which the roller travels, such that oneface of said channel primarily pushes on the rolling face of the rollerto move the stack toward its destination during the beginning of theaction, and a second opposing face of said channel primarily pushesback, to slow and stop the roller as it reaches its destination. A thirdface of the cam may face inward toward the axle (being the inwardsurface or “bottom” of said channel), and may largely be coaxial withthe axle, serving to keep said roller directly between said first andsecond faces of said channel. A portion of said third face, towards theend of the movement of the roller through the stack axial motion, mayengage said roller to push against the outer face of said roller,thereby moving said roller toward the axis of rotation, or otherwise, inorder to move said roller back to its—inactive position. A magnet,centripetal force, detent, or other mechanism may be used to keep saidroller in its inactive position until otherwise actuated.

Actuation of the Roller

A roller and its roller-arm may be actuated by a mechanism which iselectrically or mechanically controlled by the sequencer. The roller maybe actuated mechanically by a solenoid, or by hydraulic, pneumatic,magnetic, or other such mechanical means. One method of actuation of aroller which is to be moved to its active position which does notrequire electric or mechanical power to be conducted to the rotatingpulley assembly via the axle, may be the use of electromagnets.Electromagnets may be fixably mounted, in an array, to the housing nearthe path of said roller, such that they may actuate the desired rollerinto its active or non-active positions (an “electromagnet-array”). Insuch a case the roller, roller-arm, or a part or parts thereof, may havecharacteristics of ferromagnetism, magnetism, or inductive magnetism, asfound in iron, a magnet, or a coil of wire, respectively, orcharacteristics of a combination thereof. An electromagnet-array may becomposed of several electromagnets, each of which are individuallycontrollable by the sequencer, arrayed in a circle near the path of aroller, in proximity to or as part of the cam, such that the roller maypass under each electromagnet, and each electromagnet may thereby exertforce on the roller when desired.

Multiple Cam Engagement by the Roller

A roller will be capable of discrete engagement with a plurality of cams(although a roller only engages with one cam at a time), in order to beavailable to complete several stack axial motions, which will enable thestack to move into a plurality of positions, which positions correspondto the several engaging positions of pulley segments contained in thestack. Referring now to FIG. 9, a series of unified pulley segmentstacks 150 is seen with a series of cams 156, a series of rollers 157and roller arms 158. Roller 157 a (corresponding to the unified stack150 a) is in the roller active position, and said roller has almostcompleted its engagement with cam 156 a. Roller 157 b and roller 157 c(with corresponding unified stacks 150 b and 150 c) are in the rolleractive position, and are seen engaging cam 156 a. Roller 157 d is seenin the roller active position, about to engage cam 156 a. In this view,several rollers can be seen engaging cam 156 a, which moves a unifiedstack 150 from its position where its second-smallest pulley segment maybe in its engaging position, to the position where said unified stack'ssmallest pulley segment may be in its engaging position. In so doing,the SSIPTS accomplishes the transition from its second-smallest pulleysegment set (“second gear”) to the smallest pulley segment set (“firstgear”). Once a roller 157 has completed its engagement with a cam 156—inthe example shown, once roller 157 a, for example, has completed itsengagement with cam 156 c—it may then be available to engage withanother cam 156 (in the example shown, cam 156 b, and so forth, untilthe end of the range of mounted cams). Said process may continue throughmultiple transitions, both from smaller pulley segment sets to largerpulley segment sets, and from larger pulley segment sets to smallerpulley segment sets, within the range of the mounted cams.

Several electromagnet-arrays may be implemented in order to facilitate aplurality of paths of said roller, so that said roller may engage aplurality of cams, where each of said paths of said roller correspondsto the path of each of the cam engaging positions.

Individual Selectable Pulley Segment Actuation by Fixably MountedActuator Components

Each electromagnet in said electromagnet-array may be energized at aprecise moment to commence the movement of a selected individual rollerto its roller active position. The actuation may occur when saidselected individual roller is proximate to said electromagnet, withoutsignificantly affecting the position of the preceding roller of anadjacent stack. Said roller and its stack may be so selected by theSSIPTS system sequencer because a key pulley segment in the currentlyengaging pulley segment set is located in said stack. As said rollerpasses under each electromagnet in said electromagnet-array, it may bethe first roller affected by each electromagnet in saidelectromagnet-array. An electromagnet may remain energized thereafter,so that subsequent rollers passing proximate to said electromagnet willeach also be so affected, and subsequently following stacks will followthe axial motion of the first stack, and therefore each pulley segmentsubsequent to the key pulley segment in the pulley segment set will besequentially moved, like the key pulley segment, to or from its engagingposition.

The best mode of the present invention is in a device requiring variablegearing between the driving member and the driven member, Oneapplication of the present invention is in vehicular transportation. Inan automobile, the present invention would replace a common powertransmission transmitting power between the engine and the wheels,allowing the engine to operate closer to its ideal operating speed forthe given road speed. The present invention may also enhance thefunction of contemporary heating, ventilation, and air conditioning(HVAC) systems, and may confer substantial efficiency and otherbenefits.

Where a chosen tooth of a first pulley segment of a first pulley segmentset, or a chosen tooth of a second pulley segment of said first pulleysegment set, is shortened or otherwise modified in order to make saidsecond pulley segment function properly as a second key pulley segment,the transition of the endless member from said first pulley segment setto a second pulley segment set is enhanced, as the circumferentialposition of said first pulley segment may be already decided.Optionally, several pulley segments in a given pulley segment set may bedesigned to be key pulley segments as deemed fit by someone skilled inthe art.

Lubrication of the pulley segments may allow said pulley segments toslide reliably between the engaging and non-engaging positions.Lubrication may be applied as a coating of a low-friction solid to thesliding faces of the pulley segments. The faces of the pulley assemblywhich mate with said faces of the pulley segments may also be appliedwith low-friction coatings of the same or different substance as thoseof the sliding faces of said pulley segments. Pressurized gas such asair may also be channeled through small holes on selected surfaces ofthe pulley assembly which mate with the sliding surfaces of pulleysegments to create a bed of escaping gas to reduce friction. Lubricationmay be applied primarily to the sliding faces of the pulley segmentswhich face away from the axis of rotation, and the sliding faces of thepulley assembly and other faces of said pulley segment which may beproximate to said sliding faces of the pulley segment which face awayfrom the axis of rotation to reduce friction caused by the centrifugalforces acted upon said pulley segment from the rotation around the axisof rotation of the pulley assembly.

Although the foregoing description relates to a specific preferredembodiment as presently contemplated by the inventors, it will beunderstood by those skilled in the art that the invention in its broadaspect includes mechanical and functional equivalents of the elementsdescribed herein.

It will be apparent that the scope of the present invention is limitedonly by the claims set out hereinbelow.

1. A key pulley segment, acting as one pulley segment in a pulleysegment set, in a synchronized segmentally interchanging pulleytransmission system, and having a distal relationship with the teeth ofa second pulley such that simultaneous engagement of an endless memberis possible, incorporating one or more shortened or completely trimmedkey pulley segment teeth, which teeth are either first or last in thepulley segment set to engage the endless member.
 2. A key pulleysegment, acting as one pulley segment in a pulley segment set, in asynchronized segmentally interchanging pulley transmission system, andhaving a distal relationship with the teeth of a second pulley such thatsimultaneous engagement of an endless member is possible, incorporatingan adjacent pulley segment with elongated or overhanging teeth features,with an extending segment portion which may or may not slidably matewith a supporting surface of the key pulley segment.
 3. A supportingsurface on a key pulley segment for an endless member, created by theshortening or complete trimming of one or more key pulley segment teeth,in a synchronized segmentally interchanging pulley transmission system.4. A unified stack comprised of multiple, staggered pulley segments,vertically connected or constructed onto one or more slidably movablecomponents, with mating features and guiding rails on their inner andouter surfaces, any of which pulley segments in the unified stack mayengage an endless member, in a synchronized segmentally interchangingpulley transmission system.
 5. A core pulley in a synchronizedsegmentally interchanging pulley transmission system, with guiding railswhich mate with the mating features on a inner surface of a mostproximate unified stack comprised of multiple, staggered pulleysegments, vertically connected or constructed onto one or more slidablymovable components, where the guiding rails of said core pulley may alsofunction as teeth capable of engaging the endless member.
 6. A series ofone or more cams, in a synchronized segmentally interchanging pulleytransmission system, affixed or fixably mounted to a chassis or housing,and a series of rollers, fixed members or other such cam followers, witha roller arm affixed to each roller, where the roller and roller arm areslidably or rotatably mounted to unified pulley segment stacks, togethercapable of moving a unified pulley segment stack by the movement of eachroller into and out of an active position, enabling its engagement witha cam, in a manner such that individual pulley segments of said stackmay be moved into or out of an engaging position.
 7. The actuation of aroller, or fixed member or other such cam follower, and its roller-arm,together into its active position, before the point of engagement of theroller with a cam, and out of its active position, after its point ofengagement with the cam, by an array of fixably mounted electromagnetslocated near the path of a roller, in proximity to or as part of the camin a synchronized segmentally interchanging pulley transmission system.8. An arrangement of multiple cams, in a synchronized segmentallyinterchanging pulley transmission system, such that discrete sequentialengagement by a series of rollers, or fixed members or other such camfollowers, together with the corresponding series of attached unifiedpulley segment stacks, is available, such that a unified pulley segmentstack may move into a plurality of positions, which positions correspondto the several engaging positions of pulley segments contained in thestack.
 9. An array of fixably mounted electromagnets, arranged such thata feature on a pulley segment or pulley segment stack in a synchronizedsegmentally interchanging pulley transmission system may be discretelyactuated, by the synchronization of the energizing of one or moreselectable electromagnets to the position and motion of the desiredpulley segment feature, which feature may be the pulley segment orpulley segment stack itself, a roller, a cam follower or other fixedmember, or some other actuator feature, when the desired feature passesproximate to the selected electromagnet or electromagnets in the array.10. A system of sequencing the energization of fixably mountedelectromagnets in an array, such that pulley segment features, whichfeatures may be a pulley segment or pulley segment stack itself, aroller, a cam follower or other fixed member, or some other actuatorfeature, such that an individual pulley segment or pulley segment stackmay be discretely actuated, in a synchronized segmentally interchangingpulley transmission system.
 11. (canceled)